Not as a Word replacement (never used Word), but Excel and Powerpoint: I switched. It took a couple of months to feel as productive. The first 2 weeks were especially hair pulling.
Much was due to the ribbon interface, which I liked, which LO doesn't have. My mind reverted to menus via Office 2000 which I cut my teeth on as a new graduate years back.
There are some things I still find odd / bewildering:
Right clicking on a block of text I have the options of both 'Text' and 'Character' which have different options. Neither of the contained options contain vertical alignment choices. Tables just feel a pain, zooming in and out as different cells / borders are clicked. Blah blah blah other small things. For my sins, I like VBA (familiar with, rather than romance).
Familiar is the key. It took a small learning curve, and I'm as productive in it as a modern version of MS Office. Much of the learning curve is having been so familiar with MS Office, sometimes things are just done differently, mainly at the UX Level. Integration for a personal and work based workflow is where Linux leaves Windows in the standing-gates was the game changer for me, and why I put myself through the learning curve.
I do feel LO's UI simply doesn't look beautiful, indeed, I feel it looks ugly. Everything is gray, some icons have shadow, some not. I have the feeling a few hundreds of hours on grouping icons, highlighting contrast in dialogue boxes, would make it a lot less 'tired' looking. Mozilla did it, I am sure LO will, and that may be a small but important tipping point.